Methods and vehicles of this type are sufficiently known from the general prior art, in particular from the mass production of passenger cars. The vehicle comprises at least one wheel by means of which the vehicle can roll on a roadway and as a result move along the roadway. If the vehicle is embodied, for example, as an at least two-track motor vehicle, the vehicle comprises at least two axles which are arranged spaced apart from one another in the longitudinal directions of the vehicle. These axles each comprise at least two wheels by means of which the vehicle can roll on the roadway. At least one of the wheels is a driven wheel by means of which the vehicle can be driven. The two wheels are usually wheels which are driven at least one of the axles.
If, for example, the wheels of the front axle are the driven wheels, the vehicle is embodied as a front-drive vehicle or as a vehicle with front wheel drive if the wheels of the rear axle are not driven. The rear axle is then what is referred to as a trailing axle, while the front axle is a driven axle. Conversely, the vehicle is embodied as a rear drive vehicle or as a vehicle with rear drive if the wheels of the rear axle are the driven wheels while the wheels of the front axle are not driven. If the wheels of both axles are driven, the vehicle has all-wheel drive or four-wheel drive.
The vehicle also comprises a brake device by means of which the vehicle which is moving along the roadway can be braked. For this purpose, at least one of the wheels of the vehicle is braked by means of the brake device. To brake the at least one wheel, at least one braking torque is applied to the wheel by the brake device.
In vehicles or motor vehicles with a conventional drive, the brake device comprises for this purpose at least one friction brake which is assigned to the wheel and by means of which the wheel can be braked. Such a friction brake comprises, for example, a brake disk which is coupled in rotationally fixed fashion to the wheel and a brake caliper which is attached to a wheel carrier and is therefore fixed to the body and by means of which the brake disk which rotates along with the wheel can be braked. The friction brake is usually activated hydraulically, with the result that the friction brake is therefore embodied as a hydraulic brake.
In vehicles or motor vehicles with alternative drives, for example in hybrid vehicles, the brake device also comprises at least one so-called recuperative brake. By means of such a recuperative brake, energy can be recovered during the braking of the wheel and therefore of the vehicle in that, for example, during the braking of the vehicle kinetic energy is converted via the recuperative brake into electrical energy, that is to say electric current. For this purpose, the recuperative brake comprises, for example, at least one generator which is driven by the wheel to brake the wheel and as a result converts mechanical energy into electrical energy. The electrical energy which is acquired or recovered in this way can be stored in at least one electrical storage device, in particular in a battery, of the hybrid vehicle.
The total braking torque which is to be applied to the wheel by the brake device is predefined, for example, by the driver of the vehicle in such a way that the driver activates, in particular presses, a brake pedal. The braking torque which is requested as a result can then be applied to the wheel, for example partially by the friction brake and partially by the recuperative brake.
Furthermore, anti-lock brake systems, which are usually also referred to as automatic lock preventers, are known from the general prior art. Such anti-lock brake systems serve to carry out braking operations with at least virtually maximum utilization of the frictional engagement between the tire and the roadway, referred to as anti-lock braking operations. In such an anti-lock braking operation, the braking torque which is to be applied to the at least one wheel by the brake device is limited at least temporarily to a predefinable value by means of a regulating device of the anti-lock brake system, to prevent, at least temporarily, the wheel from locking relative to the roadway.
This limitation of the braking torque is carried out, for example, as a function of at least one regulating value which characterizes the slip of the wheel relative to the roadway. The idea on which such an anti-lock brake system is based is that maximum braking decelerations can be achieved as a function of the state of the roadway and the tire of the wheel given specific slip values. By limiting the braking torque, the braking torque is set in such a way that, at least during the greater part of the anti-lock braking operation, the slip is as close as possible to the optimum slip value for the greatest possible braking deceleration, with the result that, on the one hand, very strong deceleration or braking of the vehicle can be implemented but, on the other, the wheel can be prevented from locking. As result, the vehicle continues, for example, to be steerable and stable, since the non-locking wheel can still absorb lateral guidance forces.
DE 10 2010 054 620 A1 discloses a method for determining braking torques of a vehicle with a traction battery, with at least one recuperative brake and at least one friction brake on at least one drive axle with the inclusion of a lateral-dynamic driving state of the vehicle. Such a traction battery is the abovementioned electrical storage device in which electrical energy, which has been recovered by means of the recuperative brake, can be stored.
The stored electrical energy can be used, for example, for electric loads and/or for driving the vehicle by means of an electric motor, with the result that operation which is particularly efficient in terms of energy and, in the case of a hybrid vehicle in particular, operation which has low consumption of fuel can be implemented. For example an electric machine which can be used as an electric motor in a motor operating mode and as the abovementioned generator in a generator operating mode can be used as the electric motor. However, it has become apparent that the operation of such a conventional vehicle is worthy of improvement in terms of the efficiency and the implementation of a particularly low consumption of energy.